Yttrium-90 Radioembolization with Resin Microspheres without Routine Embolization of the Gastroduodenal Artery

Yttrium-90 radioembolization using MIRD dosimetry with resin microspheres

OBJECTIVE

To review the technical feasibility of resin microsphere (SIR-Spheres®) yttrium-90 radioembolization prescribed using the medical internal radiation dose (MIRD) model.

METHODS

All radioembolization procedures for hepatic malignancies using resin microspheres with MIRD model between November 2015 and February 2019 were included in this IRB-approved study (n = 60). Student's T test was used to compare prescribed activity based on MIRD and BSA models. Adverse events were assessed immediately, 30 days, and 6 months post-treatment.

RESULTS

Sixty radioembolizations were performed in 54 patients (age 68 ± 9 years, 48-87 years, 35% female). Mean prescribed activity calculated by the MIRD model (target absorbed dose 120-200 Gy for primary and 80-200 Gy for metastatic liver cancers) was 1.7 GBq (0.3-6.4) compared with 0.6 GBq (0.12-2.1) if BSA had been used (p < 0.0001). The prescribed activity was successfully delivered in 93% (56/60) treatments. Prophylactic embolization and anti-reflux catheters were used in 20% (12/60) and 5% (3/60) treatments, respectively. No immediate post-procedural complications occurred. Abdominal pain was the most common clinical Grade 3 CTCAE in 30 days (10%) and 6 months (12%). Radiation pneumonitis occurred in 3 (5%) patients but no radiation-induced gastric ulcer or radiation-induced liver disease occurred.

CONCLUSION

MIRD dosimetry results in higher prescribed activity compared with BSA dosimetry with resin microspheres. MIRD prescribed activity with target absorbed doses up to 200 Gy can be successfully administered without prophylactic embolization in selected patients.

KEY POINTS

•MIRD dosimetry results in higher prescribed activity compared with BSA dosimetry for radioembolization. •MIRD dosimetry can be used for yttrium-90 resin microsphere radioembolization with acceptable safety profile.

Single-Institution Experience with Selective Internal Radiation Therapy (SIRT) for the Treatment of Primary and Secondary Hepatic Tumors

Purpose: We aim to provide results of the real-world experience of a single center in Lebanon on the use of radioembolization to treat liver-only or liver-dominant tumors. 

Methods: This retrospective review included patients who were evaluated for radioembolization between January 2015 and June 2017 and who had a lung shunt fraction of 20% or less. Tumor responses were determined using the response evaluation criteria in solid tumors (RECIST).

Results: Of the 23 Arab patients with a median age of 64 years (range, 36-87 years), eight had hepatocellular carcinoma, four had cholangiocarcinoma, and 11 had liver-only or liver-dominant metastases from other primary cancers. Most (n=17) had multifocal lesions, and 13 had a history of branched (n=8) or main (n=5) portal vein thrombosis. When appropriate, the gastroduodenal artery and middle hepatic artery were embolized for consolidation of radiotherapy; 18 patients required arterial coil occlusion, two had their cystic artery occluded, and one developed cholecystitis, which was successfully treated with antibiotics and supportive care. Another patient developed a post-radioembolization complication-a peptic ulcer unrelated to arterial reflux of microspheres because both the gastroduodenal and right gastric arteries were occluded. The median time to progression was seven months (range, 3-36 months), and median overall survival from radioembolization was 12 months (range, 3-40 months). Tumor responses included five complete responses, 13 partial responses, one stable disease, and four cases of progressive disease. 

Conclusion: Performing radioembolization in a non-referral, private center in Lebanon resulted in good patient outcomes with few complications.

Catheter-Directed Computed Tomography Hepatic Angiography for Yttrium-90 Selective Internal Radiotherapy of Hepatocellular Carcinoma Reduces Prophylactic Embolization of Extrahepatic Vessels

OBJECTIVES

To determine the rate of prophylactic embolization of extrahepatic vessels in patients undergoing yttrium-90 selective internal radiotherapy (⁹⁰Y SIRT) for hepatocellular carcinoma (HCC) with the use of catheter-directed computed tomography hepatic angiography (CD-CTHA).

MATERIALS AND METHODS

This retrospective study included 186 HCC patients who received ⁹⁰Y SIRT from May 2010 to June 2015 in a single institution. All procedures were performed in a hybrid angiography-CT suite equipped with digital subtraction angiography (DSA) and CD-CTHA capabilities. CD-CTHA was performed during pre-treatment hepatic angiography. ⁹⁰Y SIRT was administered approximately 2 weeks later. Selective prophylactic embolization of extrahepatic vessels was performed if extrahepatic enhancement was seen on CD-CTHA or if an extrahepatic vessel opacified on DSA/CD-CTHA despite the final microcatheter position for ⁹⁰Y microsphere delivery being beyond the origin of this vessel.

RESULTS

Thirty-five patients (18.8%) required selective embolization of extrahepatic vessels. Technical success of ⁹⁰Y SIRT was 99.5%. Two patients (1.1%) developed radiation-induced gastrointestinal ulceration, and one (0.54%) developed radiation-induced pneumonitis. Extrahepatic uptake of ⁹⁰Y microspheres was seen in the gallbladder of one patient without significant complications.

CONCLUSION

The use of CD-CTHA in ⁹⁰Y SIRT of HCC was associated with a low rate of prophylactic embolization of extrahepatic vessels while maintaining a high technical success rate of treatment and low rate of complications.

LEVEL OF EVIDENCE

Level 4, case series.

Gallbladder Radiation Protection in SIRT-Quantitative Anatomical Study of Hepatic Vasculature

Introduction: This study was designed to assess quantitatively a safe position of the microcatheter during the SIRT (Selective Internal Radiation Therapy) procedure, in order to minimize the risk of non-target spheres leaking. Materials and Methods: Retrospective analysis of the distance of the tip of the microcatheter from coiled or patent non-target arteries was measured during ^99mTc-MAA work-up procedure. Frequency of extrahepatic leaking during work-up and SIRT procedures was evaluated. Results: There were 85 patients who underwent 98 work-up procedures. There were 64 radioembolizations. There were 44 gastroduodenal, 51 right gastric, and 54 cystic artery embolizations performed. Extrahepatic ^99mTc-MAA leaking was observed in 33 cases: 16 to gallbladder, four to a gastric wall, nine to the duodenum, one to the intestinal wall, and three to the abdominal wall. Leak in ^99mTc-MAA was also related to the presence of additional arteries (p = 0.009). There were 34 proximal and 31 distal to cystic artery ^99mTc-MAA injections resulting in 12 vs. four leaks, respectively (p = 0.039, RR-2.5). Mean distance of the tip of the microcatheter from the origin of the cystic artery was 20 mm (minimum of 2.1 mm and maximum of 53 mm) proximally and 10 mm (minimum 1 mm and maximum 51 mm) distally (ns). Conclusions: Leaking in ^99mTc-MAA (^99mTc - labelled macroaggregated albumin) was related to the presence of additional arteries. Regardless of cystic artery embolization, it is 2.5 times safer to inject microspheres distal to its origin, compared to proximal injection. Cystic artery origin relative to the right hepatic artery division usually necessitates embolization of the former.

Red Flags, Pitfalls, and Cautions in Y90 Radiotherapy

Radioembolization with yttrium-90 (Y90) microspheres is increasingly used to palliate patients with liver-dominant malignancy. With appropriate patient selection, this outpatient treatment is efficacious with limited toxicity profile. This article reviews common scenarios that can present in daily practice including evaluation of liver functions, evaluation of previous therapies, integrating Y90 into ongoing systemic therapy, determining performance status, and considering retreatment for patients who have already undergone Y90 who have hepatic dominant progression. Finally, we address the importance of evaluating tumors in potential watershed zones to maximize treatment response by using c-arm computed tomography. Many of these potential variables can overlap in an individual patient. By considering these factors individually, the consulting Interventional Radiologist can present a thorough treatment plan with a full description of expected outcomes and toxicities to clinic patients.